import React, { Component } from 'react'
import './index.css'

export default class index extends Component {

  //全选checkbox的回调
	handleCheckAll = (event)=>{
		this.props.checkAllTodo(event.target.checked)
	}
  //清除已完成任务的回调
	handleClearAllDone = ()=>{
		this.props.clearAllDone()
	}

  render() {
    const {todos} = this.props
    //已完成的个数
		const doneCount = todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)
		//总数
		const total = todos.length
    return (
      // 不能用defaultChecked 只在第一次起作用
        <div className="todo-footer">
        <label>
            <input type="checkbox"  onChange={this.handleCheckAll} checked={doneCount === total && total !== 0 ? true : false}/>
        </label>
        <span>
            <span>已完成{doneCount}</span> / 全部{total}
        </span>
        <button onClick={this.handleClearAllDone} className="btn btn-danger">清除已完成任务</button>
    </div>
    )
  }
}
